Handler记录

package com.example.handler;import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;import java.net.URL;import java.net.URLConnection;import android.annotation.SuppressLint;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.HandlerThread;import android.os.Looper;import android.os.Message;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MainActivity extends Activity {private mHandler Handler1;private Button btn1;private Button btn2;private mHandler1 myHandler;private looperHandler loopHandler1;Thread t;//private Handler myHandler = new Handler();@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);btn1 = (Button)findViewById(R.id.btn1);btn2 = (Button)findViewById(R.id.btn2);//一个线程只有一个Looper，但是可以有多个handler对象，每个handler对象只对应一个线程//这里在一个线程里面创建了2个handler，handler将消息都放入了该线程的Looper中。//Looper提供的是一个消息循环机制，而handler的作用是对消息进行处理，包括发送消息、处理//handler发送的对象有2个：1.runnable对象，2.message对象，同时对应了runnable线程队列和消息队列//handler的使用方法答题分3步：//1.创建handler对象//2.创建runnable和message//3.调用post或者sendmessage方法将对象添加到Looper队列中Handler1 = new mHandler();myHandler = new mHandler1();//通过创建一个HandlerThread线程可以实现向这个线程的消息队列发送消息//1.创建一个 handlerthread//2.启动这个线程//3.用线程的getlooper参数去实例handler对象HandlerThread looper = new HandlerThread("handler_thread");looper.start();//这里创建的handler对象是绑定在新线程里面的，这里设置looper对象要使用线程的looper，//如果使用getmainloop获取的主线程的looper，那这个handler处理的是主线程looper里面的//消息loopHandler1 = new looperHandler(looper.getLooper());//按键将一个runnable对象放入队列中，当runnable发送到队列后，会立即返回，//不会管是否被执行、成功等。而具体执行是等到队列排到这个runnable对象后，//由系统拿来执行。btn1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stub//这里直接将runnable对象放入线程队列中，但是并没有创建新的线程，仍然是在创建//runnable对象的线程中。//myHandler.post(mrunnable);//标准的新线程启动方法,可以看到打印的线程ID已经改变t = new Thread(mrunnable);t.start();sendmsg();System.out.println("start---->");}});btn2.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubmyHandler.removeCallbacks(mrunnable);try {t.stop();} catch (Exception e) {// TODO: handle exception}System.out.println("stop---->");}});System.out.println("MainActivity threadid------->"+Thread.currentThread().getId());}private void sendmsg() {// TODO Auto-generated method stubMessage msg = new Message();Bundle b = new Bundle();b.putString("sendMsg", "test send msg to child thread!!");msg.setData(b);loopHandler1.sendMessage(msg);}//这个类用来实例handler对象static class looperHandler extends Handler{URL url;URLConnection conn = null;InputStream is = null;InputStreamReader isr = null;BufferedReader br = null;@Overridepublic void handleMessage(Message msg) {// TODO Auto-generated method stubsuper.handleMessage(msg);Bundle b= msg.getData();String str = b.getString("sendMsg");System.out.println("looperHandler get from mainthread---->"+str);//打印可以看出，这里是个新线程，可以直接在这里处理一些耗时操作System.out.println("looperHandler threadid---->"+Thread.currentThread().getId());//使用网络操作测试是否是在新线程里try {url = new URL("http://iframe.ip138.com/ic.asp");conn = url.openConnection();is = conn.getInputStream();isr = new InputStreamReader(is,"gb2312");br = new BufferedReader(isr);String input = "";while ((input = br.readLine()) != null) {str += input;}} catch (Exception e) {e.printStackTrace();}}public looperHandler() {            super();        }                /* 这个构造方法必须有 ,通过实例handler对象中的getlooper参数去获取         * 新的线程的Looper         */        public looperHandler(Looper looper) {            super(looper);        }                }static class mHandler1 extends Handler{@Overridepublic void handleMessage(Message msg) {// TODO Auto-generated method stub super.handleMessage(msg);//Message.obtain();Bundle b= msg.getData();String str = b.getString("runnable1");String str2 = b.getString("sendMsg");System.out.println("Handler1 get from runnable---->"+str);System.out.println("Handler1 get from sendMsg---->"+str2);}}static class mHandler extends Handler{public mHandler(){} public mHandler(Looper looper){ super(looper); }@Overridepublic void handleMessage(Message msg) {// TODO Auto-generated method stubsuper.handleMessage(msg);Message.obtain();Bundle b = msg.getData();String string = b.getString("sendMsg");String string2 = b.getString("runnable1");System.out.println("mHandler threadid---->"+Thread.currentThread().getId());System.out.println("handleMessage get from sendMsg---->"+string);System.out.println("handleMessage get from runnable---->"+string2);}}private void sendMessage() {// TODO Auto-generated method stubMessage msg = new Message();Bundle b = new Bundle();b.putString("sendMsg", "sendMsg");msg.setData(b);Handler1.sendMessage(msg);}private Runnable mrunnable = new Runnable() {@Overridepublic void run() {// TODO Auto-generated method stub//每个handler在发送消息时都需要自己单独的message对象//这里如果共用一个，回导致应用无法响应。/*Message msg = new Message();Message msg1 = new Message();Bundle b = new Bundle();Bundle b1 = new Bundle();b.putString("runnable1", "runnable1");b1.putString("runnable1", "runnable1");b.putString("sendMsg", "sendMsg");b1.putString("sendMsg", "sendMsg");msg.setData(b);msg1.setData(b1);myHandler.sendMessage(msg);Handler1.sendMessage(msg1);*///sendMessage();//当runnable对象排队到它时，会执行run方法，执行完毕后消息会废弃，//如果需要重复发送，必须重新将runnable对象放入队列中//可以看到，如果去掉下面一行代码，那么runnable对象只会执行一次。//myHandler.postDelayed(mrunnable, 3000);System.out.println("runnable1 threadid------->"+Thread.currentThread().getId());try {//这里是从线程发出消息，如果要实现循环，需要使用外套while，然后使线程定时睡眠//这样它是运行在新线程当中Thread.currentThread();Thread.sleep(3000);Message msg = new Message();Message msg1 = new Message();Bundle b = new Bundle();Bundle b1 = new Bundle();b.putString("runnable1", "runnable1");b1.putString("runnable1", "runnable1");b.putString("sendMsg", "sendMsg");b1.putString("sendMsg", "sendMsg");msg.setData(b);msg1.setData(b1);myHandler.sendMessage(msg);Handler1.sendMessage(msg1);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}//这里如果使用post，会将这个runnable对象放入到主线程的looper中//通过每次定时放入来实现循环发出消息，他是运行在主线程里面myHandler.postDelayed(mrunnable, 3000);}};@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();if (id == R.id.action_settings) {return true;}return super.onOptionsItemSelected(item);}}